Web-treatment rollers of polyurethane

ABSTRACT

This disclosure is directed to rollers for the treatment of textile webs and similar materials wherein the rolls come in contact with treating solutions applied to the webs. The roll consists of a cylindrical core having a shell of a material with an elastic surface. The surface comprises a polyurethane coating having a Shore A hardness of 86 to 96.

United States Patent 1191 [111 3,779,051 Kuesters 1 Dec. 18, 1973 [54]WEB-TREATMENT'ROLLERS OF 3,087,231 4/1963 Martin et al. 100/155 RPOLYURETHANE 3,101,563 3/1963 ()shzin i 1 1 .1 68/258 3,133,340 5/1964Finelli 29/132 X Inventor: Eduard Kuesters. Gladbachcr 3,412,411 11/1968Cohn et 11. 8/151 Strusse 457, Krefeld, Germany 3,490,119 1/1970Fukujama et a1. i 29/132 1 3.511,?29 5/1970 Williams 29/132 X 1221 M0911973 3,685,443 8/1972 KUSICTS 29/132 x [21 Appl. No.: 329,982

Related S Application Data Primary Examiner-Alfred R. Guest [63]Continuation of Ser. No. 3 5,362, May 7, 197(1. A[mmeyPaul H. Hellerabandoned.

- [57] ABSTRACT [52] 11.8. C1 68/248, 29/132, 100/176 51 Int. Cl. D06145/22 T1115 dlsclosure dlrecwd rollers for the treatment [58] A Field ofSearch u 29/] 10, 1 16 R 1 16 AD of textile webs and similar materialswherein the rolls 29/1295 3268/2414, 248 258; 100/155, come in contactwith treating solutions applied to the 1 176; 8/l47 148 151 webs. Theroll consists of a cylindrical core having a shell of a material with anelastic surface. The surface [56] References (med comprises apolyurethane coating having a Shore A UNITED STATES PATENTS hardness f86 to 3,002,866 10/1961 Gartrell et a1. 29/132 X 2 Claims, 2 DrawingFigures PAIENTEnum a ma /NVEN7'04 EDUAQO Mu/ssTeRs BACKGROUND OF THEINVENTION The rolls conventionally used for the treatment and squeezingof webs comprise discs of nonwovenfabrics pressed together and fittedonto a core or shaft. The nonwoven fabrics contain cellulose fibers ornatural fibers and a portion of synthetic fibers, preferably apolyamide. The nonwoven fabric discs are saturated and made firm by arubber-like solution. The high squeezing capacity of rolls built of suchdiscs is due to a great extent to the nonwoven fibers which are at theouter circumference of the roll and which have the characteristic ofabrush with bristles which have been pressed together very tightly. Thischaracteristic of the roll surface results in a high elasticity and arelatively good deformation capability of the surface. When using theserolls for squeezing textiles, the elastic surface of the rollspenetrates the recesses built up by warp and weft and removes a maximumvolume of water.

The above type of surface characteristic is, however, notsuitable forprocesses other than squeezing textile webs. For example, theimpregnation of synthetic resins into a web cannot be performed withthese rolls in asatisfactory manner. During such impregnation, the resinworks itself into the fine pores of the roll surface with theconsequence that the rolls quickly become covered with a thick resincoating. Similarly, in the process of impregnating textile webs with arubber-like substance the rolls become covered with a rubber coatingwhich clings to the surface of the rolls and makes them unsatisfactory,for continued use. The abovedescribed rolls also create difficultieswhen applying a dye to a textile surface because the rolls do notprovide a sufficiently uniform application of the dye and result inconsiderable difficulties in cleaning the roll surface. Additionally,the rolls are not sufficiently elastic and during prolonged operationthe edges of the webs mark the rolls. Dyeing tests must be performedwith newly refaced rolls of this kind due to different densitiesobtained during pressing of the non-woven fabric onto the rolls.

A rubber cover for the roll is often not satisfactory because it lacksthe required hardness and elasticity. Rubber rolls, depending on thequality of the material to be treated, generally produce results whichare about to percent worse than that of the fiber rolls.

An important requirement in the technique of dyeing textiles is to applya minimum amount of liquid. It has been determined that the so-c'alledmigration of dye is insignificant at a certain minimum liquid level.This liquid minimum is near the swelling capacity of the fibers. Itistherefore necessary when dyeing to closely and uniformly control thepressure applied to treated webs.

' Anobject of this invention is to provide a roll which avoids theaforementioned disadvantages; which provides a substantial squeezingeffect upon a web in order to prevent or diminish the migration of thedye particles; and wherein dyeing is accomplished with the minimumapplication of liquid.

A further object of this invention is to provide a roll which issuitable for the treatment of textile webs to 2 which dyes, syntheticfinishings, and'latex impregnations are applied.

Yet another object of this invention is to provide the roll havingsufficient elasticity and hardness for the above noted uses.

These and other objects are obtained with the roll hereinafter describedin greater detail.

THE INVENTION This invention is directed to a roll having a shell with asurface of dense polyurethane ofa Shore A hardness of 86 to 96. The rollaccording to the present invention is of sufficient hardness to preventthe formation of too wide a nip between companion pressing rolls sincetoo wide a nip would not be conducive to the required maximum removal ofliquid. The roll surface is highly elastic and therefore completelysmooths undesired deformation which occurs, for example, during feedingof web edges, folds or foreign bodies. In addition, the roll has theability to maintain its shape and stability; this is of utmostimportance since during dyeing the smallest deformation of the cylinderroll results in visual imperfections. The roll of the present inventionis also resistant against dyes and other impregnating materials. Theroll shell has a smooth surface which prevents adhesion of dyes andfinishing materials, and makes the removal of these foreign bodieseasier.

Preferably, the shell for the rolls of the present invention has a ShoreA hardness of about 94 for the treat ment of textile webs with materialslike dyes, synthetic finishings, latex impregnations, and otherapplications of such materials to webs. The polyurethane shell ispreferably applied by coating the core of the roll, in accordance withconventional coating techniques. In order to accomodate the very widerolls used in the textile industry, often having a length of about l.6meters, it is desirable to use a controlled deflection roll in thepresent invention. The detailed mechanism of a controlled deflectionroll is set forth' in U.S. Pat. No. 2,908,964. This type of constructionprevents the deflections and uneven operations which would otherwiseoccur with large rolls.

The drawings show a preferred embodiment of this invention in which thepolyurethane shell is used in connection with a controlled deflectionroll such as is described in US. Pat. No. 2,908,964.

FIG. 1 shows a pair of cooperating rolls, each of the same construction,with a partial cross sectional cutaway of the upper roll which shows theinterior thereof.

FIG. 2 shows a side view of the rolls including a partial longitudinallycross sectioned view along lines 2-2 of FIG. 1.

Each of the rolls generally designated as 1 and 2 comprises a shell 5which consists of polyurethane fixedly mounted on a controlleddeflection roll 3 of circular cross section. Polyurethane shell 5 has aShore A hardness of 86 to 96, for example, a Shore A hardness of 94 hasbeen found vto be very effective. Polyurethane shell 5 may bemanufactured by coating the shell 6 of the controlled deflection roll 3with an adhesive and a liquid polyurethane. The particular adhesive andthe polyurethane used to obtain the desired hardness are ings 11 areprovided to position the shell 6 with respect to the stationary shaft 7.The shaft 7 being of such a size as to define within the inner surfaceof the shell 6 an intermediate space 9.-The longitudinal seals 8 dividethe space into two compartments, one on the'pressure applying side ofthe roll and the other on the opposite side of the roll, 12 and 13respectively. The compartment 12 on the nip or pressure applying side ofthe roll is sealed in the axial direction at each end thereof, so as toform a longitudinal pressure chamber on the working side of the rollextending the length thereof which can be filled by a fluid, said endseals are adjacent bearings 11. The ends 4 of the shaft 7 extend beyondthe ends of the shell 6 and can be mounted in frames not shown. Inoperation the deflection of the roll can be controlled through theadjustment of the fluid pressure inside the compartment 12. The fluidpressure may be applied through the bore 10. Further details of thestructure in operation of a controlled deflection roll such as hereindescribed are set forth in US. Pat. No. 2,908,964.

The invention is not limited to the embodiment shown. For example, theroll used need not be a controlled deflection roll.

The novel rolls of this invention provide for the improved processing oftextile webs which are treated thereby. The method of this inventioncomprises passing a textile web through rolls having a polyurethaneshell. The textile web is uniformly squeezed and maximum effectivenessof the applied material, i.e., dye, finish, latex, etc., is obtained.

This invention has been described in terms of specific embodiments setforth in detail. Alternative embodimerits will be apparent to thoseskilled in the art in view of this disclosure, and accordinglysuchmodifications are to be contemplated within the spirit of theinvention as disclosed and claimed herein.

What is-claimed is:

1. Cooperating rolls forming a nip resistant to materials such as dyes,synthetic finishings and latex impregnations, each of said rollscomprising a cylindrical roll body coated with polyurethane in the formof a dense uniform shell having a Shore A hardness of from 86 to 96 andfixed on said roll body, and the latter being formed by a controlleddeflection roll, said rolls forming a nip width when under pressures notexceeding that conducive to the maximum removal of liquids from saidwebs while being elastic under said pressures to a degree uniformlysqueezing said webs during feeding of web edges, folds, foreign bodiesand the like.

2. Cooperating rolls forming a nip resistant to materials such as dyes,synthetic finishings and latex impreg nations, each of said rollscomprising a cylindrical roll body coated with polyurethane in the formof a dense uniform shell having a Shore A hardness of about 94 and fixedon said roll body, and the latter being formed by a controlleddeflection roll, said rolls forming a nip width when under pressures notexceeding that conducive to the maximum removal of liquids from saidwebs while being elastic under said pressures to a degreeuniformlysqueezing said webs during feeding of web edges, folds, foreignbodies and the like.

1. Cooperating rolls forming a nip resistant to materials such as dyes,synthetic finishings and latex impregnations, each of said rollscomprising a cylindrical roll body coated with polyurethane in the formof a dense uniform shell having a Shore A hardness of from 86 to 96 andfixed on said roll body, and the latter being formed by a controlleddeflection roll, said rolls forming a nip width when under pressures notexceeding that conducive to the maximum removal of liquids from saidwebs while being elastic under said pressures to a degree uniformlysqueezing said webs during feeding of web edges, folds, foreign bodiesand the like.
 2. Cooperating rolls forming a nip resistant to materialssuch as dyes, synthetic finishings and latex impregnations, each of saidrolls comprising a cylindrical roll body coated with polyurethane in theform of a dense uniform shell having a Shore A hardness of about 94 andfixed on said roll body, and the latter being formed by a controlleddeflection roll, said rolls forming a nip width when under pressures notexceeding that conducive to the maximum removal of liquids from saidwebs while being elastic under said pressures to a degree uniformlysqueezing said webs during feeding of web edges, folds, foreign bodiesand the like.